If you look at http://iframehost.com/help/addapp and http://iframehost.com/newapp you'll see that they have a very nice way of filling in all the settings for the app. You just create the new app with a name/namespace, then copy the app id & secret key you get, fill in these at iframehost.com/newapp, and all the rest of the settings appear "automagically" in the app settings on facebook.

I understand that the app id & secret key together allows the iframehost-server to send the rest of the stuff to FB, but could anyone point me in the right direction, or even better, give me an example or something?